Requesting login and password when trying to access any Windows function.

[fvm]

|=Good morning.
Here at the company, we have the proxy configured, its filter is by ACL, there are 3 configuration groups with IP range to enable what is available. When I configure the proxy on the terminals, it's asking for login and password when trying to access something on Windows. I've checked but couldn't find what it could be, has anyone encountered this before, can you help?
Thank you.

login-to-view